A motor vehicle suspension stop is generally made up of two rings having balls disposed between them to run on raceways defined by the two rings. A cage is placed in the ball chamber and serves to keep the balls in position therein.
Document US-A-2006/0008192 provides for portions in relief on the inner and outer radial faces of a cage formed by strip portions, the portions in relief serving to guide balls that are received in the cells of a strip portion forming the cage, thereby making it possible to take advantage of the small radial thickness of the cage. Given its shape, such a cage is not adapted for use within a suspension stop.
Document DE-A-100 2005 039736 also discloses making a cage provided with projecting portions that come to bear simultaneously against the raceways. That cage tends to be subject to wear, because it makes simultaneous contact with both raceways and interferes with the balls bearing against the raceways.
Known suspension stops are subjected to reversals in the direction of pivoting and to friction that exists within said stops, tending to move the cage vertically within the ball chamber, to such an extent that it can strike against an edge of one of the upper or lower rings of the stop via an outer radial portion of the cage referred to herein as its lip. This impedes pivoting of the rings relative to each other and may lead to the lip being ruptured. The cage is then ineffective and, under the worst circumstances, there is a risk of one or more of the balls becoming jammed in the ball chamber. The suspension stop is then blocked. The radial deformation of the ring as subjected to repeated large amplitude oscillations at low speed may also lead to rupture thereof by fatigue.
The invention seeks more particularly to remedy those drawbacks by proposing a novel suspension stop of operation that is made more reliable, and that remains simple to fabricate and to use.
To this end, the invention provides a motor vehicle suspension stop comprising a first ring, a second ring, balls bearing against two raceways respectively defined by the first ring and by the second ring, and a cage for holding the balls between the raceways, the stop being characterized in that the cage is provided with abutment pins for bearing against the raceways, the pins being distributed on both sides of a radial midplane of the cage that contains the centers of cells in the cage, and in that wherein the an axial distance between the ends of the abutment pins is strictly less than a height of a radial section of a ball chamber formed the minimum distance between the raceways.
By means of the invention, the abutment means provided on the cage make it possible, as a function of the direction of rotation of the rings of the suspension stop relative to each other and taking account of the friction between the balls and the age, to limit axial movement of the cage, i.e. movement thereof parallel to the central axis of the stop. This avoids a so-called “flip-flop” or rocking phenomenon in which the cage deforms to come to bear in alternation against the edges of the first and second rings, with high levels of friction and a risk of rupture. The abutment means serve to come into contact with the raceways so that the other portions of the cage, that are not designed for this purpose, do not run the risk of being damaged or ruptured by unwanted contact with the rings of the stop. Since the axial distance between the ends of the pins is less than the minimum distance between the raceways, there is always clearance between the cage and at least one of the raceways, thereby limiting wear of the cage and enabling the balls to bear simultaneously against both raceways, without being hindered as a result of the presence of the cage.